This project aims to develop an automated device for extracting mesenchymal stem cells (MSCs) in clinically relevant quantities from adipose tissues for treating many serious diseases, including myocardial infarction, diabetes, liver cirrhosis and graft-versus-host disease. Over 400 clinical trials to date have established the feasibility, safet, and in some cases efficacy of autologous and allogeneic MSC therapies to treat these diseases. However, the results are inconclusive due to the lack of standard and optimized MSC preparation protocols and the loss of MSC characteristics and functions as MSCs are extensively expanded. We have developed a concept prototype device to show that adipose tissue may contain at least an order of magnitude more MSCs than previously reported, opening the opportunity to use un-cultured primary MSCs as a high potency substitute for ex vivo expanded MSCs currently used in clinical trials. The device will have a unique configuration to (1) enable rapid and efficient enzyme digestion providing MSCs in clinically relevant quantities, (2) fully integrate MSC extraction steps of tissue washing, enzyme digestion, cell separation, and debris removal in a closed system format, and (3) enable automation readily, so that the MSC extraction process can be performed efficiently, safely and reproducibly. In Phase I, we will (1) optimize the prototype device and operating protocols to maximize viable MSC recovery, which is the most difficult and important step in MSC preparation, and (2) use the primary MSCs to prevent and treat graft versus host disease (GVHD) in a humanized mouse model as an example to demonstrate the preclinical safety and efficacy of our primary MSCs. Our team includes medical device experts, stem cell biologists, humanized mouse experts, and physicians who have worked together successfully on multiple projects. The proposed device represents an essential tool for enabling MSC therapies to be highly effective and ultimately the standard of care for treating many life-threatening and hard-to-treat diseases.